Wave guide switch



March 4, 1958 COLEMAN, JR 2,825,878

WAVE GUIDE SWITCH 3 Sheets-Sheet 1 Filed April 11, 1956 STANDBY TRANSMITTER .\lIII!lililillliiiiiwmliimwmi lllllll [III TRANSMITTER 57 MAIN Rf:

FIE I INVENTOR. RICHARD R. CoLEmAN,JR.

BMM

March 4, 1958 COLEMAN JR 2,825,878

WAVE GUIDE SWITCH 3 Sheets-Sheet 2 Filed April 11, 1956 INVENTOR- PICHA no R. COLEMAALJR BY? z 2 ATTORNEH'S March 4, 1958 R COLEMAN JR 2,825,878

r WAVE GUIDE SWITCH Filed April 11, 1956 3 Sheets-Sheet 3 FIE 4 IN V EN TOR.

RICHARD RCOLEMANJR.

MMM

ATTORNE v.5

Unite WAVE GUlDlE SWITCH Richard R. Coleman, in, Dallas, Tex., assignor to Collins Rfaiiio Company, Cedar Rapids, Iowa, a corporation owa Application April 11, 1956, Serial No. 577,501 3 Claims. (Cl. 333-98) This invention relates generally to switches for waveguides which permit lenient tolerances in their proportioning, while maintaining a low standing-wave ratio.

Many prior types of microwave switches require critical tolerances in their construction. It is, therefore, a primary object of this invention to provide a microwave switch which can allow relatively large tolerances in the manufacture of its parts and which can allow relatively simple mechanical adjustment.

It is accordingly another object of this invention to provide a waveguide switch that permits economy of construction. For example, the component parts of this invention may be made of cast metal having a relatively small amount of machining.

Although the invention avoids critical tolerances, it is capable of obtaining a very low standing-wave ratio over a large band of microwave frequencies.

The invention uses an armature member that is movable relative to a base-plate member. The armature member has a flat side, which is adjacent to a fiat side of the base-plate member. Incoming and outgoing waveguides are terminated on one side of the base-plate member, which is formed with openings that align with the waveguides. The armature member may be formed with U-shaped passages, which are capable of connecting different pairs of waveguide openings in the base-plate member, as the armature is moved relative to the base plate.

Waveguide chokes are machined in either of the adjacent sides of the base-plate member and armature. The chokes may be of known types, such as the plugged type.

A non-critical spacing is permitted by this arrangement between the armature member and the base-plate member; and it is necessary that the spacing exceed a minimum value, wherein undesired resonances may occur, or exceed a maximum value, wherein excessive loss may occur. The range of spacing is sufficiently large at such a microwave frequency as 7000 megacycles to avoid difficult tolerances. Generally, a spacing variation from 0.035 to 0.117 of a wavelength is permitted between the base-plate member and the armature without any substantial deterioration in the standing-wave ratio caused by the waveguide switch.

Furthermore, lateral offset in the alignment of the engaged waveguides in the armature member and the baseplate member is permissible without substantially deteriorating the transmission of energy across the gap. The amount of lateral offset may vary from zero up to approximately the same order as the maximum permissible spacing variation.

This invention provides a reciprocating type of waveguide switch, which is capable of being operated either manually or by a motor.

For example, a switch made according to this tion may be operated manually by a toggle lever, which might extend through the panel of microwave equipment.

,When remote control is desired for a switch made according to this invention, it permits a single unidirecinven- Patented Martional motor with a single cam and a single cam operated switch to provide position sensing, position limiting, and movement between two opposite positions. Accordingly, no bidirectional motor with limit and reversing switches is necessary, as is often needed in many types of waveguide switches.

Also, this invention allows the armature of its waveguide switch to have passages terminated by energy dissipating material in order to permit, for example, a transmitter to be tuned, while dissipating its load in the attenuating member of the switch.

The armature in this invention is explained herein as a two position device, although it will become apparent that it can utilize a greater number of positions.

Further objects, features and advantages of this invention will become apparent to a person skilled in the art upon further study of the specification and drawings, in which:

Figure l is a sectional-schematic representation of an illustrative embodiment partially taken along section 1111 in Figure 2;

Figure 2 is a cut-away perspective view of an embodiment of the invention;

Figure 3 views one side of a base-plate member which may be utilized in the invention; and,

Figure 4 shows a wiring diagram that may be used to remotely control the invention.

Now referring to the invention in more detail, Figure 1 illustrates a waveguide switch for a dual-transmitter antenna arrangement. Figure 1 shows a base-plate member 10, which is formed of conducting material with three openings 11, 12, and 13, that align respectively with waveguides 16, 17 and 18. The waveguides connect in a conductive manner to one side of base-plate 10' and, for example, may be bolted to the base plate.

The waveguides may have any cross-sectional configuration. However, in this embodiment, they are each assumed to have a rectangular cross-section. Accordingly, openings 11, 12 and 13 are rectangular.

On the opposite side of base plate 10, a plurality of filter chokes 21, 22, and 23 are respectively grooved circularly in base plate 10 about the waveguide openings. The chokes may be of the plugged type, which are shown in Figure 3. v

The chokes generally will be formed by machining a groove circularly about each waveguide opening. The depth of each choke groove is approximately one-quarter wavelength but is determined experimentally in most cases. However, theoretically it is essential that there be an apparent one-half wavelength at the operating frequency between the edge of the waveguide and the bottom of the choke, in order that the short circuit at the bottom of the choke appear along the opening in the waveguide. The plug configuration generally prevents radiation of spurious modes.

The plugging may be done by inserting conductive material in that portion of the choke opening, which is. adjacent to the short sides of the waveguide openings in the base plate.

An armature member 26 is provided and also is made. of a conducting material similar to the material of base plate 10. Armature member 26 is formed with a U- shaped waveguide passage 27, which has the same crosssectional configuration as the waveguide openings in base plate 10.

The spacing between the centers of the waveguide openings in base plate 10 are made equal to the spacing between the centers of the entrances to the U-shaped opening in armature member 26.

Also, a pair of linear openings 28 and 29 formed in armature 26, and these openings also have crosssections identical to the openings .tormed in base plate 10,,

Linea v ope ng 2 s pos t n on one s de f -s aped opening 27; and its center is spaced from the adjacent end of U-shaped opening 27 by a distance equal to the spacing between adjacent openings in base plate '10.

The other linear opening 29v is positioned on the opposite side of U-shaped opening 27, and is similarly spaced from it .by a distance equal to the spacing between adjacent openings in base plate 10.

Dummy loads 31 and 32 which may be polyiron or some other energy dissipating material providing proper impedance values, are inserted at the ends of linear openings 28 and 29 on the side .of armature 26 opposite base plate 10. The dummy loads present to the waveguide passages an impedance which substantially matches the characteristic impedance .of the connecting waveguides.

In Figure l a main transmitter 37 is lconnected to waveguide 1&5; and a standby transmitter 36 is connected to the remaining waveguide 13. Center waveguide 17 connects to an antenna 33.

Armature 26 is provided with two positions. Gne position is shown in Figure l; and it connects a standby transmitter 36 to dummy load 32, and connects main transmitter 37 to antenna 38.

The second position requires armature 26 to be moved to the right in Figure 1. It connects main transmitter 37 to dummy load 31 and connects standby transmitter 36 to the antenna.

A spacing is shown in Figure '1 between base plate 10 and armature 26, and this spacing is non-critical and may vary from about 0.035 wavelength to about 0.l'l7 wavelength without causing any substantial standing-wave ratio in the connecting waveguides due to the waveguide switch. Accordingly, an average spacing of around 0.075 wavelength may generally be specified so that a significant variation of tolerance in either direction from it is permissible. For example, at 6500 megacycles per second, if'a spacing of 0.136 inch is used, a tolerance variation of plus or minus 0.070 of an inch is permissible without causing any substantial standing wave ratio, which can be of the order of .05 decibel. When plug type openings are used, the maximum spacing may be further increased without much increase in loss.

Figure 2 shows the invention embodied in a motor operated waveguide switch, which may be made of cast metal components. The switch is situated on a supporting plate 40. A base plate is hired to one side of supporting plate 40; and openings (not visible in Figure 2) are formed through supporting plate 40 and base plate 4-1. Waveguides, such as 42, 43 and 44, connect to the outer side of supporting plate 41 and align with its openings. An armature member 46, which may be a metallic casting, is pivotally supported by members 47. Members 47 are pivotally supported at one end from blocks 43 fixed to supporting plate 40 and are pivotally connected at their other ends to armature member 46.

Pivoting members 47 permit a swing type of reciprocating motion for armature member 46. The opposite positions of the reciprocating swing are limited mechanically by the length of members 47. Armature 46 may touch blocks 48 at each of its opposite positions, but this is generally not desirable because armature 46 operates with a harmonic motion from a crank mechanism. Therefore, no mechanical stop is actually required, the stop being inherent in the length ofthe stroke of a crank; 51. However, armature 46 may touch blocks 48 at each of its opposite positions; and thus, the height of blocks is proportioned to provide an average spacing of about 0.025 wavelength between armature 46 and base plate 41 at the opposite positions of armature d6.

Reciprocating motion is provided to armature .45 through an adjustable link member 49 which .pivotally connects at one end to one of the pivot members 47.

The. opposite end of an; 4? is connected to and driven by the end of crank member 51. Crank member .51 is supported by a crank shaft 52, which is rotatably supported by a bracket 53 fixed to supporting plate 40.

A desirable result of the harmonic nature of the reciprocating motion imparted to armature 46 is that no shock is caused when armature 46 comes to rest at either of its two positions.

A cam 54 is fixed to the opposite end of crank shaft 53, and also a gear 56 is fixed to crank shaft 53.

Gear 56 is driven by means of a Worm gear 57, which is rotatedby a unidirectional motor 58.

A cam follower 61 includes a follower wheel 62, which rides on the surface of cam 54. Follower 61 actuates a double-throw single-pole switch 63, which is fastened to supporting plate 40.

The unidirectional rotation of motor 58 provides reciprocating actuation of armature 56, through the crank and lever mechanism. Cam 54 permits sensing of the extreme reciprocation positions, which arethe two positions provided for the switch in Figure 2.

Figure .4 shows a wiring diagram, which may be used with motor 58 and switch 63 to connect them to a remotely positioned control switch 66, that may be used to obtain remote control over the waveguide switch in Figure 2. Cam actuated switch 63, includes a pole .67 and double-throw contacts 68 and 69. At one position of cam 54, pole 67 will engage one contact 68; and after cam 54 hasrotated pole 67 will engage opposite contact 69.

Remote control switch 66 is also a single-pole doublethrow switch, which has a pole 71 and contacts 72 and 73.

The contacts of control switch 66 are respectively connected to the contacts of the waveguide double-throw switch 63 by leads 76 and 77. Pole 71 of the control switch is connected to one side of a power-source 78 by means of a lead 7?, and the power source connects on its opposite side to motor 58. The pole of cam operated switch 67 is connected to the opposite side of motor 5 8 by a lead 81.

Figure 4 shows the control system in a non-energized state, wherein the waveguide switch is in one of its positions. The waveguide switch may be actuated to its opposite position by throwing control switch 66 to its opposite position. Then, a circuit is completed through contact 72 and the motor, which rotates crank 51 approximately 180 degrees, where the circuit is interrupted due to the cam which then moves pole 67 from contact 68 to break the circuit through the motor.

However, where remote control is not necessary for the waveguide switch, it is relatively easy to provide direct manual control. in this case, armature 46 may be reciprocated by a toggle arrangement.

Futhermore, where manual control is possible and space is-at a premium, pivoting members 47 may be eliminated. Instead, a sliding mechanism may be provided between base plate 40 and armature 41, wherein armature 41 may be slid to its two positions. Therefore, the switch does not require the additional space occupied by the armature during its swinging action. Such a switch may be mounted with its armature member directly behind a panel; and .a projection may be fastened to the armature and may extend through a slot in the panel, whereby the armature may be actuated by the projection.

A single armature member may have many more U- shaped passages than is shown in the illustrated embodiment and, accordingly, may simultaneously provide} switching among a large plurality of waveguides. For example, thearmature may be formed with many U- sh'aped openings located side by side. In such case, the base plate will be formed with a corresponding number ofopenings, which connect to a corresponding number of waveguides that are switched in response to armature movement.

While particular forms of the invention have been shownanddescribed, it is to be understood that the invention is capable of many modifications. Changes, therefore, in the construction and arrangement may be made without departing from the scope of the invention as given by the appended claims.

What is claimed is:

1. A waveguide switch comprising a base-plate member formed with a plurality of openings passing through it, first, second and third waveguides received on one side of said base-plate member and aligned respectively with different of said openings, said waveguides and openings all having the same cross-sectional configuration, said waveguide openings being equally spaced and laterally aligned, an armature member supported adjacent to said baseplate member on its side opposite said waveguides, a U-shaped passage formed in said armature member having the same cross-section as said waveguides, the ends of said U-shaped opening being substantially alignable with adjacent waveguides, said armature member and baseplate member being spaced from each other between about 0.035 to about 0.117 wavelength at the operating frequency of said waveguides, means for laterally moving said armature member relative to said base-plate member from one position in which the ends of said U-shaped passage align with said first and second waveguides to a second position in which the ends of said U-shaped passage align with said second and third waveguides, with chokes formed about the opening in said base-plate member on its side adjacent to said armature, said armature member being also formed with first and second openings, with each opening having the same crosssectional configuration as said waveguides, said first and second openings positioned on opposite sides of said U- shaped passage and spaced therefrom by an amount equal to the spacing between said base-plate openings, said first and second openings being alternately alignable with a difierent one of said base-plate openings at given positions of said armature, dummy loading means plugging the ends of said first and second openings opposite their ends adjacent to said base-plate member.

2. A waveguide switch comprising a base-plate member formed with a plurality of openings through it, a Waveguide choke formed in said base-plate member about each of said openings on one side of said base-plate member, a plurality of waveguides terminating respectively at said openings on said base-plate member on its side opposite said chokes, said waveguide openings spaced equally from each other, said openings and waveguides all having the same cross-sectional configuration, an armature member received on the opposite side of said baseplate member from said waveguides, said armature mem ber spaced from said base-plate member between about 0.035 to about 0.117 wavelength at the operating frequency of said waveguides, a U-shaped passage having the same waveguide cross-section formed in said armature member with ends received adjacent the choked side of said base-plate member, a frame member attached to said base-plate member, a plurality of pivoting members, each having one end pivotally connected to said frame member, and each having its other end pivotably connected to said armature member to enable reciprocal movement of said armature member with respect to said base-plate member, a linking member being pivotably connected to said pivoting members, a crank member having a shaft rotatably supported by said frame member, and said crank member rotatably coupled to said linking member, whereby unidirectional rotation of said crank operates said waveguide switch between opposite positions.

3. A waveguide switching mechanism as defined in claim 2, also comprising a unidirectional motor being supported by said frame member, gear-transmission means coupling said motor to said crank-member shaft, a cam fixed to said crank member shaft to enable sensing of said switch position, a cam follower engaging said cam periphery, a first single-pole double-throw switch fixed to said frame member, said first switch having its pole coupled to said cam follower and actuated therefrom, a control switch being a second single-pole double-throw switch, with its opposite contacts respectively connected to the opposite contacts of said first single-pole doublethrow switch, and a power source connected in series with the poles of said switches and said motor, whereby said waveguide switch is controllable remotely by said control switch.

References Cited in the file of this patent UNITED STATES PATENTS 2,629,048 Dyke et al Feb. 17, 1953 2,759,152 Charles Aug. 14, 1956 FOREIGN PATENTS 1,076,926 France Nov. 3, 1954 

